Recording artists Kesha arrives to the premiere of 'Planes: Fire & Rescue' at the El Capitan Theater in the Hollywood section of Los Angeles, California, July 15, 2014.

Pop star Kesha's former music producer on Monday said allegations that he had raped the singer were lies, and hit back at a "trial by Twitter" backed by some of music's biggest names over Kesha's bid to extricate herself from a recording contract.

Dr. Luke, whose real name is Lukasz Gottwald, posted a series of tweets saying that people supporting Kesha's claims of sexual assault against him were "getting behind an allegation only - motivated by money."

"I didn’t rape Kesha and I have never had sex with her. Kesha and I were friends for many years and she was like my little sister," the producer said.

"But lives can get ruined when there’s a rush to judgment before all the facts come out ... It’s sad that she would turn a contract negotiation into something so horrendous and untrue," he added.

Anger and sympathy for the "Tik Tok" singer swelled after a New York judge ruled on Friday that Kesha, 28, could not be released from her six-album recording contract with Sony Music.

Kesha claimed in a 2014 lawsuit that Dr. Luke raped and emotionally manipulated her. Dr. Luke countersued and both cases have yet to come to trial.

Singer Taylor Swift has donated $250,000 to Kesha to help her financial needs, while Lady Gaga, Kelly Clarkson, Miley Cyrus and Ariana Grande are among hundreds who have posted messages on Instagram and Twitter to the fast-growing #FreeKesha campaign.

"Most important for Kesha, is that these beautiful, powerful women are standing behind her, letting the world see how powerful the truth is!" Kesha's mother, Pebe Sebert, posted on Twitter on Sunday.

Dr. Luke's attorney, Christine Lepera, on Monday accused the singer and her legal team of conducting a "trial by Twitter, using a vicious smear campaign to ruin his reputation."

She said the allegations in Kesha's lawsuit are "outright lies that have been advanced to extort a contract renegotiation and money."

Lepera said Kesha, who burst on the music scene in 2009, was "already 'free' to record and release music without working with Dr. Luke as a producer if she doesn’t want to."